Nylon films are particularly desirable in packaging applications because of their inherent strength and puncture resistance, grease resistance, thermoformability and oxygen impermeability. In such packaging applications, it has frequently been found desirable to combine a nylon to a second layer of an ethylene polymer or copolymer without the use of a solvent-based adhesive. Particularly satisfactory ethylene copolymers in this application are the "Surlyn.RTM." ionomer resins which are partially neutralized ethylene/methacrylic acid copolymers commercially available from E. I. du Pont de Nemours and Company. Such ethylene copolymers, when laminated to nylon, provide heat sealability at low temperatures which is particularly desirable in packaging applications.
Bonding of the nylon and ethylene polymer components in such composites is difficult, and the bonds are often weakened on exposure to moisture.